1990 S-10 4x4 Manual Tranny Fluid?

[Frankie02]

What kind of fluid am I supposed to run in my transmission?

 

[LargeCarManX2]

Use a synthetic ATF in this transmission. Mobil 1 ATF will work.

 

[cosynthetics]

Upgrade to a fluid that is made for synchro transmissions rather than a generic ATF.

Amsoil MTF
Royal Purple SyncroMAX
RedLine MTL

 

[Pablo]

I wouldn't use anything thinner than this:

Amsoil ATD

Or indeed give MTF a try:

Amsoil MTF

 

[mechtech2]

ditto cosynthetics